Most buildings enclose space which must be heated and cooled for occupancy. Depending on the location of the structure on Earth and the season, the building's envelope maintains a temperature differential between the inside and the outside. The ability of the envelope to reduce the flow of heat into or out of the volume is called its thermal resistance. The greater the thermal resistance a portion of the envelope has, the less energy is required to maintain that temperature differential. In the building industry, resistance to conductive thermal loss is measured in the unit “R” (“R-value”). It is the inverse of the unit of thermal conductivity, often represented by the unit “I” (or alternatively “U” or “U-value”).
People are depleting natural resources at an ever-increasing rate. The scientific community is working on ways of harnessing power from “renewable” resources in nature (e.g., solar energy, wind energy, biofuels, tidal currents). Until methods are developed which fully utilize these sources, and implementation of such energy generation is wide-spread, most energy requirements must be satisfied via fossil fuel or nuclear technology.
In order to gradually reduce the use of fossil fuels for the conditioning of living space, various agencies promulgating construction requirements for new construction are continually increasing the insulation requirements (“R” values) for the building envelope. These requirements are approaching a point where typical framing materials, from which structures are usually constructed, will not be large enough in dimension to contain the increased thicknesses of insulation—typically inexpensive thermal insulation made of fiberglass blankets or loose-packed cellulose, for example. The next round of mandated insulation requirements may require the use of metal framing instead of wood, in order to provide thicker wall cavities and roof framing to accommodate thicker insulation. Construction professionals who are accustomed to designing and building wood structures would be greatly disadvantaged by such changes, and the economic impact of such changes on many tens of thousands of people will likely not be insubstantial.
Some alternative options for increasing the R-value of building envelopes may include use of varieties of foam insulating materials. However, such materials are substantially more expensive than fiberglass blankets or cellulose. Moreover, most, if not all foam insulation materials are made directly from petrochemicals, a depletable resource. Fiberglass is made from silicon, which is available in great abundance.
Further, the number of existing buildings in the world far outweighs the number of buildings that will be built in the near future The majority of such buildings were constructed prior to the development of more recent energy-conserving standards for building envelope performance. Indeed, most residential and other types of structures were constructed prior to any mandated thermal efficiency requirements whatsoever. Even structures that were built after the institution of thermal efficiency requirements were not built to today's efficiency standards. Effectively retrofitting existing buildings with traditional insulating materials is usually a costly endeavor.
Moreover, the absorption of moisture by fiberglass and cellulose insulation materials from interior or exterior sources has the effect of reducing the effective “R” values of the insulation, as compared with R-values of the same material when dry. That is, the addition of moisture can increase the thermal conductivity of an insulating material. If sufficiently severe, this phenomenon can even result in an R value that is less than air (i.e., a situation worse than no insulation at all). It is likely, therefore, that the insulation of structures currently insulated with fibrous insulation have not completely maintained their thermal efficiency.
There is, therefore, a need for construction materials and methods of construction and installation thereof, for improving the thermal resistance of existing structures as well as increasing the overall thermal resistance of new construction. The present disclosure addresses these needs.